Compasses have been used for many years for navigation, technical diagrams and drawing. The tool is designed to allow the user to draw accurate circles of varying diameters. Navigation compasses were used on sail boats to determine course direction and position based on the wind. These were different from the other use of the word compass, which indicates which direction is north.
The most basic form of a compass involves two arms connected at the top by a hinge allowing them to pivot. On one arm there is a sharp point which is placed at the center of the circle and on the other a pen or pencil to actually draw the circle. The writing instrument can either be built into the compass arm itself or attached independently by the user.
A bow compass follows the same basic design as the drawing compass, but has a screw built in between the arms which can be adjusted by turning a wheel in the middle. This means it is able to hold the arc of the circle more accurately than the manually changed drawing compass. It is called a bow compass as the arms are manufactured in a slight arc to allow it to be adjusted.
This version is a combination of both the drawing and bow compass. The arms are pivot in the middle and cross each other, similar to a pair of scissors. This design uses a screw mechanism to hold it in place like the bow compass to maintain accuracy.
The drop compass only has one pivoting arm which holds the writing instrument, while the other is fixed in position. The compass is adjusted using a screw arrangement similar to the bow compass.
The two arms are mounted on a straight edge ruler and are fixed by screws at the top. This means adjusting the compass is very accurate and it can also draw larger circle than the other versions.
- Photo Credit compass image by Christopher Hall from Fotolia.com
What Is a Math Compass?
A math compass is a metal or plastic V-shaped drawing tool with a clamp on one end to hold a pencil and...
How to Use Drafting Tools
Drafting tools are an architect's best friend. You can't begin to apply your advanced drafting skills until you've learned how to select...
How to Make a Simple Rheostat
A rheostat is another name for a variable resistor. This simple component drops a certain amount of voltage in a circuit, which...
How to Draw a Large Circle Without a Compass
I don't know about you, but when I try to draw circles by hand, they end up looking more like mangled potatoes...
What Are the Different Types of Compasses?
Compasses are a navigational tool in many different walks of life. From casual countryside trekkers to massive ocean liners, the compass helps...
How to Use a Geometric Compass
A geometric compass is a mathematical tool used to calculate the distance between points and create arcs. Use a geometric compass with...